Hello, we are currently planning our house and have a floor area of 147 sqm (8.20 x 12.01 m). We initially wanted to build two full stories but have now decided on a 1 1/2-story design with a knee wall height of 1.50 m (4 ft 11 in) due to cost considerations.
We want to use a gable roof with a 45-degree pitch.
I wanted to find out what the usable floor space would be in this case.
On Monday, we visited a smaller model home that had a knee wall height of only 1 meter (3 ft 3 in), and the roof pitch seemed shallower to me. When I was upstairs in the attic space, I was quite surprised that I could only stand upright in the middle, and there was hardly any usable space elsewhere.
We want to use a gable roof with a 45-degree pitch.
I wanted to find out what the usable floor space would be in this case.
On Monday, we visited a smaller model home that had a knee wall height of only 1 meter (3 ft 3 in), and the roof pitch seemed shallower to me. When I was upstairs in the attic space, I was quite surprised that I could only stand upright in the middle, and there was hardly any usable space elsewhere.
A quick rough calculation:
With a roof pitch of 45%, you lose about one meter of width on each side for every meter of height gained.
An 8.20m (27 feet) wide house minus the walls leaves roughly 7.50m (25 feet) of interior width.
Up to the ceiling of the second floor, you can roughly estimate the usable width decreases by 1m (3 feet) per side, leaving about 5.50m (18 feet) at ceiling height.
The floor structure on the upper floor plus a person’s height of 1.80m (5 ft 11 in) adds roughly another 2 meters (6 feet 6 inches) in height, which further reduces the usable width by 4m (13 feet).
Effectively, you have no more than 1.50m (5 feet) of width where you can actually stand upright.
Depending on the floor build-up, personal height, and wall thickness, this can be less or slightly more.
With a roof pitch of 45%, you lose about one meter of width on each side for every meter of height gained.
An 8.20m (27 feet) wide house minus the walls leaves roughly 7.50m (25 feet) of interior width.
Up to the ceiling of the second floor, you can roughly estimate the usable width decreases by 1m (3 feet) per side, leaving about 5.50m (18 feet) at ceiling height.
The floor structure on the upper floor plus a person’s height of 1.80m (5 ft 11 in) adds roughly another 2 meters (6 feet 6 inches) in height, which further reduces the usable width by 4m (13 feet).
Effectively, you have no more than 1.50m (5 feet) of width where you can actually stand upright.
Depending on the floor build-up, personal height, and wall thickness, this can be less or slightly more.
With a house width of 8.20 m (27 feet), the ridge is 4.10 m (13 feet 5 inches) higher than the eaves, calculated as half the width. With a knee wall height of 1.50 m (5 feet) — which is quite substantial combined with a 45° roof pitch — this results in a total height of 5.60 m (18 feet 5 inches). Adding the ground floor ceiling height of 2.85 m (9 feet 4 inches), the allowed eaves height must be 4.35 m (14 feet 3 inches) and the ridge height 8.45 m (27 feet 9 inches).
Starting from the 1.50 m (5 feet) knee wall, a room height of 2.42 m (7 feet 11 inches) is reached just 92 cm (36 inches) from the exterior wall, so the strip with full room height is 6.36 m (20 feet 10 inches) wide. A room height of 2.00 m (6 feet 7 inches) is achieved after only 50 cm (20 inches), resulting in a width of 7.20 m (23 feet 7 inches).
With 94% of this area qualifying, this clearly counts as a full legal story, as the roof slope does not reduce this.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
Starting from the 1.50 m (5 feet) knee wall, a room height of 2.42 m (7 feet 11 inches) is reached just 92 cm (36 inches) from the exterior wall, so the strip with full room height is 6.36 m (20 feet 10 inches) wide. A room height of 2.00 m (6 feet 7 inches) is achieved after only 50 cm (20 inches), resulting in a width of 7.20 m (23 feet 7 inches).
With 94% of this area qualifying, this clearly counts as a full legal story, as the roof slope does not reduce this.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
You can also consult a professional and plan according to your individual needs.
Individual requirements are usually not available in model homes, and special requests there often come with an additional charge.
A plan tailored exactly to your needs is only offered by independent designers (if they are willing to do so). You can still take that plan to various home builders.
By requesting quotes from different builders using the same plan, you can get an idea of realistic prices. In the meantime, you can simply trust your designer.
Individual requirements are usually not available in model homes, and special requests there often come with an additional charge.
A plan tailored exactly to your needs is only offered by independent designers (if they are willing to do so). You can still take that plan to various home builders.
By requesting quotes from different builders using the same plan, you can get an idea of realistic prices. In the meantime, you can simply trust your designer.
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